Diaphragm pump



Dec. 17, 1968 R. MCFARLAND 3,415461 DIAPHRAGM PUMP Fnd sept. 1, 1988United States Patent Office Patented Dec. 17, 1968 3,416,461 DIAPHRAGMPUMP Rolland McFarland, Crystal Lake, Ill., assignor to Hills- McCannaCompany, Carpentersville, Ill., a corporation of Illinois Filed Sept. 1,1966, Ser. No. 576,704 4 Claims. (Cl. 103-150) ABSTRACT OF THEDISCLOSURE` There is disclosed a pump comprising a diaphragm having acentral portion of progressively increasing thickness and an integralaxially extending projection connected to an actuating member by afitting extending over the projection and a transversely disposed pin.

The present invention relates to a novel pump structure, and morespecifically to a novel diaphragm pump.

It has heretofore been proposed to provide a pump having a flexiblediaphragm with means mechanically connected to the diaphragm foractuating the diaphragm in at least one direction during a pumpingoperation. For

example, it has been proposed to provide a diaphragm structure whereinthe diaphragm is hydraulically actuated in one direction andmechanically pulled in an opposite or return direction. While certain ofsuch heretofore proposed pumps have generally been satisfactory,diaphragm wear and leakage problems have been encountered.

An important object of the present invention is to provide a noveldiaphragm pump structure wherein the diaphragm is mechanically actuatedin at least one direction and wherein the diaphragm and a mechanicalactuating element are constructed and connected in a manner whichprecludes any possibility of leakage and minimizes any possibility ofdiaphragm wear.

A further important object of the present invention is to provide anovel pump structure of the above described type which is of simple andeconomical construction which may be easily assembled.

Other objects and advantages of the present invention will be comeapparent from the following description and the accompanying drawingswherein:

FIG. 1 is a partial sectional view showing a pump structureincorporating features of the present invention; and

FIG. 2 is a fragmentary partal sectional view taken generally along line2-2 in FIG. 1.

Referring now more specifically to the drawings wherein like parts aredesignated by the same numerals throughout the various figures, a pumpstructure 10 incorporating features of the present invention comprisescomplementary body members 12 and 14 adapted to be detachably securedtogether by screws, bolts or other suitable fastening means. The bodymembers 12 and 14 respectively present opposing annular seats 16 and1-8. A flexible diaphragm 20 which is described more fully below isdisposed with its annular margin clamped between the seats 16 and 18 andfunctions in combination with the body member 14 and defining a pumpingchamber 22. The diaphragm also serves to separate the pumping chamber 22from another chamber 24 in the body member 12 which accommodateshydraulic actuating fiuid as will be described below.

The body member 14 is formed with a fluid inlet 26 communicating withthe pumping chamber 22 and connected through inlet passageway means 28with an inlet conduit 30. In the embodiment shown, check valves 32 and34 are connected in series in the passageway means 28 for preventing thereverse flow of fiuid through the passageway means. The check valves aresecured in position by a suitable fitting 36.

The body means 14 is also formed with an outlet port 38 communicatingwith the pumping chamber 22 and with outlet passageway means 40.Additional check valves 42 and 44 are disposed in the outlet passagewaymeans 40 for preventng reverse flow of fiuid. The check valves 42 and 44are retained in position by a fitting 46 which is adapted to beconnected with an outlet conduit 48.

The diaphragm 20 is adapted to be flexed back and forth within thechambers 22 and 24 during a pumping operation. As will be understood,movement of the diaphragm toward the left as viewed in FIG. 1 will forceor pump fluid from the chamber 22 through the check valves 42 and 44 andinto the outlet conduit 48.

Means are provided for hydraulically actuating the diaphragm 20 towardthe left as viewed in FIG. 1 or, in other words, through its pumpingstroke. As indicated above, the chamber 24, is provided for hydraulicactuating fiuid. The chamber 24 communicates with and includes a bore 50and a reduced diameter bore 52 which are filled with hydraulic fiuid. Areservoir 54 for the hydraulic fiuid' is provided at the upper side ofthe body member 12 and is enclosed by a cover 56.

A valve unit 58 is disposed between the reservoir 54 and passageways 60and 62 communicating with the chamber 24 and the bore 50. The valve unit58 is adapted to permit hydraulic fiuid to flow from the reservoir so ascompletely to fill the spaces of the chamber 24, the bores 50 and 52 andthe passageways 60 and 62. At the same time the valve unit 58 isconstructed for permitting air to escape from these spaces whereby toinsure that the spaces are completely filled with the liquid.

In order to actuate the hydraulic fiuid and thus the diaphragm 20 towardthe left as viewed in FIG. 1, a mechanical piston or plunger 64 isreciprocably disposed in the bore 52. A pressure relief valve 65 isdisposed between the bore 50 and the reservoir for permitting hydraulicfiuid to return to the reservoir in the event the pressure in thechamber 24 increases during the forward or working stroke of the pistonto a level which may cause injury to the diaphragm. Any suitable means,not shown, may be connected with the piston 64 for reciprocating thepiston. As will be understood, such piston actuating means may be madein accordance with any of a variety of heretofore known and usedstructures.

While the piston 64 serves to actuate the hydraulic fluid and thediaphragm toward the left, the valve unit is provided with spring meansfor actuating the diaphragm toward the right during the return stroke ofpiston 64 for minimizing any possibility of cavitation in the hydraulicactuating fiuid and for causing the diaphragm more positively to followthe reciprocating movement of the piston. In accordance with thefeatures of the present invention the spring means is constructed andconnected with the diaphragm in a manner so as to preclude leakagethrough the diaphragm and minimize any possibility of injury to thediaphragm while at the same time providing the desired efliciency inoperation. More specifically, the spring means comprises a compressionspring 66 disposed within the bore '50 and having one end seatingagainst a fixed annular abutment 68 which in turn is supported by a snapring 70 disposed in an annular groove or seat in the wall of the bore50. A hollow tubular connecting rod or stem 72 is connected with thediaphragm in a manner described below and extends axially in the bore50. The stem has an internal diameter similar to and communicates withthe bore 52. Apertures 73 provide communication between the interior ofthe stem 72 and the bore 50. The stem 72 presents an annular fiange 74at an end thereof opposite from the abutment 68 which flange is engagedby'the spring 66 so that the stem or connecting rod 72 is biased towardthe right as viewed in FIG. l or, in other words, toward a diaphragmretracting position.

The diaphragm 20 comprises a 'body having relatively thin planarperipheral portion 76 which merges with a relatively thick centralportion 78. The peripheral and central portions are integrally moldedfrom a suitable tough resilient rubber, Synthetic rubber, plastic orother suitable material. The central and peripheral portions arepreferably formed so that they provide a substantially coplanar surfacefacing the working or pumpiug cbarnber 22, which surface preferablycovered with a laminated film or sheet material liner 80 of plastic,metal or other material inert to the fluid being pumped through thechamber 22, whereby to protect the main body of the diaphragm from thefiud.

As shown in the drawings, the relatively thick central portion 78 of thediaphragm merges with a projection 82 molded integrally therewith andfrom the same material as the remainder of the diphragm body, whichprojection extends axially rearwardly of the diaphragm or, in otherwords, axially into the bore 50. A transverse aperture 84 is providedthrough the projection 82 for accommodating a pin 86 which in turnextends through ears 88 and 90 of a fitting 92 assembled over the end ofthe projection 82. The fitting 92 is adapted to be connected with thestem 72.

In the embodiment shown, the fitting 92 and the stem 72 are formed withcomplementary threads 94 for detachably connecting the two partstogether. With this constmction, it is seen that the connection betweenthe diaphragm and the stem '72 is located entirely at one side of themain portions of the diaphragm whereby there is no possibility ofleakage through the diaphragm. More precisely, the aperture whichreceives the pin 86 is at one side of and does not eXtend through thecentral portion 78 of the diaphragm. Furthermore, it will be observedthat the projection 82 merges with the relatively thick portion 78 ofdiaphragm which gradually diminishes in thickness from adjacent theprojection substantially to the peripheral portion 76, Whereby toaccommodate the stresses imposed on the diaphragm by the spring meanspulling on the projection 82 and to minimize any concentration ofstresses during fiexing of the diaphragm and thereby promote a longeruseful working life for the diaphragm. In certain instances, it isdesirable to hold or otherwise secure a tubular liner 96 within thetransverse aperture 84 for accommodating the connecting pin 86 andfurther minimizing any possibility Of injury to the diaphragm structure.

It will be noted that during assembly of the pump structure, the spring66 and diaphragm stem 72 are dsposed within the bore 50 and secured inposition by the abutment 68 and snap ring 70 prior to assembly with thediaphragm. Then the fitting 92 which has previously been connected tothe diaphragm 20 is threaded into the end of the stem 72 and theperipheral portion 76 of the diaphragm is positioned against the seat16. Prefera'bly the peripheral portion of the diaphragm is provided withannular ribs 100 which are adapted to fit within complementary groovesformed in the seat 16 for minimizing any possibility of leakage past theperiphery of the diaphragm. Then the valve body member 14 is positionedagainst the diaphragm and the main body member 12 and is bolted orotherwise secured. If desired, additional annular ribs 102 may beprovided on the diaphragrn for engaging in complementary grooves formedin the seat 18 or on the body member 14.

While a preferred embodiment of the present invention has been shown anddescribed herein, it is obvious that many structural details may bechanged without departing from the spirit and scope of the appendedclaims.

The invention is claimed as follows:

1. A pump comprising means including a fiexible resilient diaphragmproviding a pumping chamber having an inlet and an outlet, valve meanscontrolling fiow of fluid through said inlet and outlet, means forreciprocating said diaphragm for accomplishing a pumping action, saidlast named means including an element connected to said diaphragm foractuating the diaphragm in one direction, said diaphragm comprising arelatively thin flexible annular portion, an integral relatively thickcentral portion, an axially extending projection integral with saidcentral portion, and means connecting said element to said projection,said means connecting said element to said projection comprises afitting disposed over said projection, pin means extending in saidprojection and connected to said fitting, and complementaryinter-engaging means on said fitting and said element detachablyconnecting said fittin g and said element.

2. A pump, as defined in claim 1, Wherein said projection has transverseaperture means therein, and said pin means extends into said aperturemeans.

3. A pump, as defined in claim 1 wherein said relatively thick centralportion is of substantially greater radial extent than said axiallyextending projection and progressively decreases in thickness fromadjacent a junction with said projection substantially to adjacent ajunction with said relatively thin annular portion.

4. A pump, as defined in claim 1, wherein said complementaryinter-engaging means comprise helical thread convolutions on saidfitting and said element.

References Cited UNITED STATES PATENTS 1,711,803 5/1929 Munday 103 1502,148,957 2/1939 Morris et al 103-150 2,267,280 12/1941 Kuhnel 230`2,575,398 11/1951 Schroeder 103-150 2,675,758 4/1954 Hughes 103-1503,075,468 11/1963 Eifel 103-44 WILLIAM L. FREEH, Primary Examiner.

U.S. Cl. X.R.

